You have to use a program that will let you resize by pixels. Then you will find that most monitors will display a picture that is 600 to 800 pixels wide without having to scroll too much to see it all. If you enter one of the weekly or monthly challenges you will have to read the rules since their is an absolute size in pixels that will be accepted as an entry.
Welcome, Mary Beth.
For posting, generally image size should be 800 pixels along the largest dimension, allowing everyone to view the entire image despite using monitors set a different resolutions. I personally limit height to 800 but go to 1080 or more along the width. Most people will be able to see your full image without scrolling.
If you will be using FM to upload, there is a size limit to the jpeg you upload. The limit is a bit flexy; usually uploads above 250K will not go thru, even though the limit is set lower.
Hope this is the info you are looking for. I believe there is additional info at the image upload section.
